Calipers.



L. E. KIRCHNER.

CALIPERS.

APPLlCATION FILED NOV. 5. 1917.

1,288,034. Patented Dec.17,1918.

INVENTOR. L I ff/R CHNER BY %Q MW ATTORNEY UNITED STATES PATENT ()FFI@.

LOUIE E. KIRCHNER, OF JEWELL, IOWA.

CALIPERS.

Application filed November 5, 1917.

To all whom it may concern:

Be it known that I, LOUIE E. KIRCHNER, a citizen of the United States,and resident of Jewell, Hamilton county, Iowa, have in vented a new anduseful Calipers, of which the following is a specification.

The object of this invention is to provide an improved construction forcalipers.

A further object of this invention is to provide an improvedconstruction for calipers in which a sliding member is mounted on astationary member and adjustable relative to a fixed caliper arm andcarries a pivoted arm adapted to be oscillated relative to said fixedarm.

A further object of this invention is to provide an improvedconstruction for calipers in which a member is slidingly mountec on astationary member bearing a graduated scale and adjustable relative to afixed caliper arm and carries a pivoted arm adapted to be oscillatedrelative to said fixed arm, said pivoted arm being extended beyond thepivot in the form of an indicator finger adapted to magnify theoscillation of said pivoted arm and indicate the same on a secondgraduated scale.

My invention consists in the construction, arrangement and combinationof elements hereinafter set forth, pointed out in my claim andillustrated by the accompanying drawing, in which Figure 1 is anelevation of my improved calipers, portions being broken away to revealinterior construction. Fig. 2 is a plan of the same. Fig. 3 is anelevation at right angles to Fig. 1.

In the construction of the device as shown the numeral 10 designates abase bar or plate on one end of which is formed an integral, laterallyprojecting stationary caliper arm 11. A sliding member 12 is mounted onand slidable longitudinally of the bar 10, by which its positionrelative to the arm 11 is adjusted. The sliding member 12 preferably iscomposed of two parallel plates mounted on opposite sides of the bar 10,as shown in Figs. 2 and 3. Spacing blocks 13, 14 are mounted between theupper portions of the plates composing the sliding member 12, and aspacing block 15 is mounted between said plates on the opposite side ofsaid bar, said plates being secured to each other by rivets 16 or othersuitable securin members passing through said blocks. 1% graduated scale17 is formed on the face of Specification of Letters Patent.

Patented Dec. 17, 1918. Serial No. 200,363.

the bar 10 adjacent the lower margin thereof, and said scale may bebased on any suitable intervals of space, as quarter-inch subdivisions.The lower margin of the bar 10 is also formed with notches or serrations18 corresponding to the subdivisions of the scale 17. Teeth 19 areformed on the upper margin of the spacing block 15 and correspond withand are adapted to engage in the notches or serrations 18 of the bar.The distance between adjacent margins of the upper spacing blocks 13-14and the lower spacing block 15 is enough greater than the width of thebar 10 to permit movement of the sliding member 12 transversely of saidbarto the end of disengaging the teeth 19 from the notches 18, wherebysaid sliding member may be adjusted longitudinally of said bar. Aneccentric latching lever 20 is pivoted on a bolt or rivet 21 passingthrough the plates of the sliding member 12 between the spacing blocks13, 14, said lever being preferably located between said plates andprojecting above the upper end thereof at inoperative position. Thelatching lever 20 is adapted to be moved to the position shown to forcethe sliding member 12 into such position that the teeth 19 are inengagement with some of the notches 18, to hold and maintain the slidingmember in adjusted position. The free end of the lever 20 preferably isnotched or scored to facilitate engagement by the finger of theoperator.

A reciprocating or sliding caliper arm 22 is mounted in slide bearings23 carried by the lowerend of the sliding member 12 and is adapted formovement toward and away from the fixed caliper arm 11, and said slidingarin preferably is pointed at its end and is in the same horizontalplane as the end of said fixed arm. The sliding caliper arm 22is-adapted to cooperate with the point of the fixed caliper arm 11 inthe measuring operation, in a common manner. An inclicating lever 24 ispivoted on the sliding member 12 by a pin or rivet 25 and is adapted foroscillation in a plane parallel to the face of said member. A segmentaltoothed rack 26 is formed on the lower end of the lever 24 and is inmesh with and adapted to be operated by a toothed rack 27 formed on orfixed to the sliding caliper arm 22. The opposite end of the lever 24 isextended and attenuated to form an indicating finger 28, and suchportion of the lever preferably is several times the length of the loweror rackhearing portion,

preferably from four to eight times as long. The point of the finger 28preferably travels beneath a keeper 29 mounted on the upper portion ofthe sliding member 12, and an arcuate graduated scale 30 is formed onsaid sliding member adjacent the orbit of travel of said point. Thegraduations of the scale 30 are based on minute subdivisions of space,here shown conventionally, to indicate, for example, one-thousandth partof an inch, but is not actually divided so minutely for the reason thatthe movement of the point of the indicating finger 28 is magnifiedrelative to the movement of the opposite end of the lever 24, andconsequently relative to the movement of the sliding caliper arm 22,because of the ratio of length of said finger and the opposite end ofthe lever. The scale 30 is therefore magnified or enlarged, relative tothe actual travel of the sliding member 22, an amount equal to theproportion of length of the-finger 28 relative to the rack-bearing armof the lever 24:, so that very fine or minute subdivisions of spacetraveled by said sliding caliper arm may be readily read on said scale80. A spring 31 is mounted on the sliding member 12 and engages theindicator finger 28 and tends to hold said finger normally at zero onthe scale 30. In suchposition the sliding caliper arm 22 preferably isat its extreme limit of move ment toward the caliper arm 11 and projectsa given distance, say one-quarter of an inch, beyond the-inner margin ofthe sliding plate 12. The scale 17 is arranged in accordance with thenormal amount of projection of the sliding caliper arm so that itsnormal distance from the fixed caliper arm 11, dependent upon theposition of the sliding plate 12 on the fixed bar 10, may be read onsaid scale 17 by the position of the inner margin of said sliding plate12. That is, the distance from the point of the arm 11 to the point ofthe arm 12 is read on the scale 17 at the inner margin of the plate 12.

In use the sliding plate 12 is first adjusted longitudinally of the bar10, the lever 20 having first been oscillated manually to unlatchingposition to permit such movement. The adjusted position of the slidingplate 12 on the bar 10 is determined roughly by the approximate diameteror thickness of the object to be measuredby the instrument, being setpreferably at the nearest quarter-inch (or other subdivision on thescale 17) to such diameter or thickness, or at some point somewhat lessthan such dibetween the points of the stationary arm 11 and said slidingarm. Through reciprocation of the sliding caliper arm 22 the lever 24 isoscillated, because of the meshing engagement of the rack 27 with thesegmental rack 26 and the finger 28 is moved on the scale 30 andindicates the fractional differ ence, between that indicated on thescale 17 and the actual diameter or thickness of the object; or in otherwords the amount of reciprocation of the arm 22 is read, in magnifiedform, on the scale 30. The scale 17 is read by the position of theforward margin of the sliding plate 12 relative to the said scale, andis added to the reading of the scale 30 to secure the completemeasurement sought. This provides a convenient and accurate means forobtaining the measurement of an object in small fractional subdivisionsof space.

The free end of the latching lever 20 projects beyond and is adapted formovement through an are wholly extraneous to the margins of the slidingplate 12, and may at all times and in all positions be under the controlof a thumb of the operator.

1 claim as my invention Calipers, comprising a bar formed with astationary caliper arm, a member slidingly mounted on said bar, said barbeing formed with a relatively coarse graduated scale, means for lockingsaid sliding member relative to said bar, a sliding caliper arm mountedfor reciprocation in the outer end of said sliding member and adapted tocooperate With the stationary caliper farm, a relatively fine graduatedscale being formed on the sliding member, a lever pivoted on saidsliding member and having a long and a short arm integrally formed onopposite sides of its pivot, the long arm of said lever acting as anindicator finger and adapted to travel on the last named scale, theshort arm of said lever being formed with a segmental toothed rack, anda toothed rack on said sliding arm engaging said segmental rack andadapted for oscillation of said lever.

LOUIE E. KIRCHNER.

Gopies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, 1). G.

